1. Field of the Invention
This invention relates to tolerance rings.
2. Description of the Prior Art
It has heretofore been proposed as shown in the U.S. Patent to Dix et al., U.S. Pat. No. 3,061,386 to provide a tolerance ring of resilient metal for seating a shaft or round rod in a receiving opening, the tolerance ring having a plurality of circumferentially arranged corrugations of uniform height and pitch, the U.S. Patent to Hulck et al., U.S. Pat. No. 3,142,887 showing the method of making such a tolerance ring.
Blaurock et al., in U.S. Pat. No. 3,700,277, show a tolerance ring of resilient metal having a plurality of rows of corrugations of the same height with the rows having corrugations both aligned and offset with respect to each other.
Blaurock et al., in U.S. Pat. No. 3,838,928 show parallel juxtaposed separated circumferential rows of alternating, trough shaped recesses and integral projections in each major face, the recesses in each face corresponding to aligned projections in the other face, the projections and recesses all being of uniform heights in opposite directions with respect to the strip on which they are formed.
It is well known that a tolerance ring with a uniform corrugation has a linear spring rate, that is the spring force increases in a linear fashion with an increase in compression. The amount of compression a tolerance ring with uniform corrugations pitch and height can withstand before exceeding its elastic limit and acquiring a permanent deformation is an average of 15% of the corrugation height. When stressed beyond its elastic limit a tolerance ring fails to function accurately.
The tolerance rings of the present invention permit of a larger range of tolerances than the tolerance rings heretofore available.
The structures presently available for slip fit, press fit or mountings with an interposed resilient or spring member for mounting roller bearings are frequently unsatisfactory because the bearing is clamped so tightly that movement cannot occur or even if axial movement is possible the radial load capacity is low or rotational movement of the race is not prevented. The tolerance ring of the present invention with a multiple spring rate can perform these necessary functions very economically and in a manner not heretofore available.